1. Field of the Invention
The present invention relates to a metallic colloid particles well suited as a label for immunological measurement and protein-staining agent, a process for producing the metallic colloid particles; a metallic corpuscular carrying body wherein said metallic colloid particles are supported on a carrier and a process for producing the metallic corpuscular carrying body.
2. Description of the Related Arts
An immunochromatographic assay method (hereinafter referred to as “ICA method”) is known as one of procedures for immunological measurement method, and is put into practical application as a simple, easy and rapid clinical diagnosis method. According to the ICA method, it is general practice to employ an antibody which is labeled with gold colloids, since bacteria and viruses are peculiarly detected thereby. However, the ICA method using gold as a label is not said to always have sufficient sensitivity, and is required to use a label having further high sensitivity. It is taken into consideration to employ platinum colloid particles that are used for staining protein as a label for an antibody, but in the case of the ICA method, smaller particle diameter of the platinum colloid particles leads to insufficient color development.
As a countermeasure thereagainst, there are proposed metallic colloid particles wherein platinum is supported on the surfaces of gold colloid particles (refer to Japanese Patent Application Laid-Open No.262638/2003 (Heisei 15), Claim). According to this invention, there are obtainable metallic colloid particles which have sensitivity higher than that of the gold colloid particles and are well suited as a labeling agent for an immunological measurement and protein-staining agent. However depending on the type of pathogenic bacterium, infective virus concentration is extremely low, and thus there are required a labeling agent for an immunological measurement and protein-staining agent each having further high sensitivity.